BEIJING — Yu Jie has picked a fight with the Communist Party of China, and if state security forces haul him away in the dark of night, there will be no one to stop them. It’s a risk Yu took knowingly when he wrote a book published this month that slammed the country’s prime minister as an “actor” shilling for an authoritarian government.

His challenge is a rarity in a nation noted for its rough treatment of dissidents, and is made all the more remarkable by the fact that Yu, an unassuming author who looks like a Beijing office worker, has no prominent family or professional connections in China to bail him out of prison.

Yu’s book, “China’s Best Actor: Wen Jiabao,” is now a closely watched test case of Beijing’s tolerance of free speech. How the government proceeds against him will either stoke fears of a growing police state or provide an example of a more nuanced leadership unhappy with criticism but willing to tolerate a certain amount.

“Doing something like this is not a joke. You have to be very serious; you have to know what you are doing,” said Bao Pu, the head of the Hong Kong publishing house that printed the book — which is banned in the mainland. “You have to be willing to accept the risks.”

Bao said that at one point he gave Yu a 24-hour last chance to “think about the consequences.”

Yu, a quiet man in silver-framed glasses and receding black hair, answered that he’s ready for what may come.

Many observers worry that it will include a jail cell.

In a recent interview at a Beijing teahouse, Yu told McClatchy the issue was much bigger than his personal story.

“The main purpose of this book is not just to criticize Wen Jiabao,” said Yu, wearing a short-sleeve polo shirt that hung loose on his narrow shoulders and slightly rumpled slacks. “To criticize the top leaders of this government is the right of every Chinese citizen. If I’m not put into prison after the book was published, I hope this will encourage more people to speak out.”

Wen Jiabao is seen by many Chinese as a grandfather figure of sorts — “grandpa” might be the better way of putting it — a smiling man who often shuttles to the scenes of natural disasters to offer condolence and support.

Yu’s book, though, is a scathing critique of Wen that describes him as another cog of a ruthless central government, a friendly face on a harsh regime. The directness of his prose is striking in a country where dissent is seldom voiced or is so veiled that it loses meaning.

“China is a nation that is obsessed with creating gods and myths, even during (President) Hu Jintao’s era of mediocrity, they still have to create the myth of a Wen Jiabao to sooth people’s lost hearts,” Yu wrote in one chapter.

Referring to the Chinese children who died recently from poisoned milk and poorly built schools that collapsed in an earthquake, Yu asked: “Mr. Wen Jiabao, what kind of relationship do those citizens that died from ridiculous causes have with the rapid development of the country’s GDP that you are so fond of talking about?”

Yu is well aware of the potential costs of airing his views in public. A longtime friend and fellow author, Liu Xiaobo, was sentenced to 11 years in prison in December on charges of subversion against the state after helping organize a petition calling for political reform.

Yu and Liu had together helped start the Independent Chinese PEN Center in Beijing in 2001, a writers’ organization that of necessity must count Chinese in exile among its membership.

About a month before his book came out, Yu said state police took him in for questioning and demanded that he stop the book’s publication. During the conversation, the police told Yu that “you may have to bear serious criminal responsibility if you insist on publishing this book; you will end up just like Liu Xiaobo,” according to an essay that Yu wrote about the experience.

The 37-year-old son of retired construction engineers would have no recourse should authorities decide to make him disappear. After years of publishing articles critical of the government, Yu said police monitor him constantly.

Those familiar with Yu say that he’s not a reckless man, but one who’s insisted on exercising the freedoms of expression listed in China’s constitution.

For both Yu and Liu Xiaobo, “they’re not going out of bounds here, they’re simply living their lives according to China’s constitution,” said Larry Siems, the international programs director in New York for PEN, a writers’ advocacy group that promotes free speech.

However, Siems noted that by doing so in China, Yu was “at great personal risk” and Liu now sits in prison.

Yu traces his activism to the evenings he and his family spent in 1989 listening to BBC and Voice of America radio broadcasts during the Tiananmen Square standoff between students and government troops that ended in the shooting of protesters. For Yu, a high school student in Sichuan province at the time, “all the education and values taught by the Communist Party crumbled to pieces.”

Asked whether after all these years he’s now trying to walk a fine line between being a dissident and being detained, Yu explained that he’s already written thousands of lines that authorities could stitch together to sentence him for at least as long as Liu.

“So I will not waste much time and energy to find a balance,” he said. “I pretend that I am living in a free-speech country, so I speak out the truth.”